Device for the electroslag casting of ingots

ABSTRACT

The present invention relates to devices for the electroslag casting of ingots. The device is characterized in that the nonconsumable cooled metal electrode used for melting the ingots is washed with gas flows, with the gas being used for washing only that portion of the electrode which is immersed in the melt, thus providing a protecting envelope about this portion. This prevents the non-consumable electrode from electrochemical destruction.

United States Patent 1191 1111 3,9 2 Paton et al. [4 Dec. 9, 1975 [5 DEVICE FOR THE ELECTROSLAG Aug. 8, 1970 U.S.S.R 1457823 CASTING 0F INGOTS Oct. 1, 1970 U.S.S.R. 1475936 [76] Inventors: Boris Evgenievich Paton, ulitsa Kotsjubinskogo, 5, kv. 21; B ri [52] US. Cl 164/252; 13/18; 75/10 R Izrailevich Medovar, Bulvar Lesi [51] Int. Cl. B221) 27/02 Ukranki, 2, kv. 8; Leonty Vasilievich [58] Field of Search 13/ 18; 164/52, 252; Chekotilo, ulitsa Scherbakovka, 49a, 10 R kv. l0; Viktor Mikhailovich Martyn, ulitsa Vernadskogo, 65a, kv. 102; [56] References Cited Viktor Leonidovich Artamonov, ulitsa Sovskaya, 9, kv. 4; Anzor UNITED STATES PATENTS Ippolitovich Bochorishvili, ulitsa 1,680,630 8/ 1928 Okell l3/l8 Vernadskogo, 65, kv. 102; Leonid Mikhailovich Stupak, Brest-Litovskoe shosse, 39, kv. 9; Anatoly Petrovich Sysenko, ulitsa Polevaya, 25, kv. 1; Valery Georgievich Popov, ulitsa Ezhena Potie, kv. 72, all of Kiev, USSR.

22 Filed: Dec. 26, 1973 21 Appl. No.: 427,526

Related US. Application Data [63] Continuation of Ser. No. 130,412, April 1, 1971,

abandoned.

[30] Foreign Application Priority Data Apr. 20, 1970 U.S.S.R. 1424449 Primary Examiner-M. J. Andrews Attorney, Agent, or Firml-Iolman & Stern [57] ABSTRACT The present invention relates to devices for the electroslag casting of ingots. The device is characterized in that the non-consumable cooled metal electrode used for melting the ingots is washed with gas flows, with the gas being used for washing only that portion of the electrode which is immersed in the melt, thus providing a protecting envelope about this portion. This prevents the non-consumable electrode from electrochemical destruction.

2 Claims, 5 Drawing Figures l I l v I: v I L... 3! 2-3 1:;00 0:.2: n- 1" ":1":- .IIQ '2 e1, 31:: 4

0 o 0 a 0a 0 7 :0 1 II I 4 0 US. Patent Dec.9,1975 Sheet 1 of2 3,924,672

Sheet 2 of 2 m E \D US. Patent Dec. 9, 1975 DEVICE FOR THE ELECTROSLAG CASTING F moors BACKGROUND OF THE INVENTION PRIOR ART Well known in the art is a method of electroslag casting of ingots by means of non-consumable graphite or silite electrodes fed with direct or alternating current.

However, the graphite and silite electrodes are not non-consumable and in the process of electroslag casting such electrodes, when subjected to the action of high temperatures and the chemical effect of the slag, are gradually dissolved thus contaminating the slag melt with foreign inclusions, i.e. with the products of dissolution of the electrodes.

Therefore, the metals being remelted are saturated with carbon, silicon, and deleterious impurities including sulphur, phosphorus, etc., and this results in deterioration of the ingot metal quality.

Investigations have shown that it is expedient to use non-consumable cooled metal electrodes for electroslag remelting of metals by means of a straight-polarity direct current. The application of such electrodes prevents the remolten metal from saturation with deleterious impurities.

However, such electrodes, especially when fed with an alternating current or a reversed-polarity direct current, are subjected to electrochemical destruction and this also leads to the contamination of the melt with foreign impurities, resulting in premature wear of the electrode itself.

The same undesirable result occurs when casting hollow ingots. In this case, the cooled metal electrode, such as a pan for shaping the inner space of the blank, is also subject to electrochemical destruction.

OBJECTS AND SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages.

The specific object of the invention is to provide a device for the electroslag casting of ingots by means of which it is possible to prevent the electrochemical destruction of the non-consumable cooled metal electrodes, thus increasing the life thereof, and also enhancing the purity of the metal being remelted.

This object is attained due to the fact that in the electroslag casting of ingots by means of a non-consumable cooled metal electrode, according to the present invention, the portion of the non-consumable electrode immersed in the melt is washed with gas flows under pressure.

This makes it possible to eliminate the electrochemical destruction of the non-consumable electrodes.

In the present device including a non-consumable cooled metal electrode provided with openings located in the portion of the electrode immersed in the melt, according to the invention, on the end wall of this portion of the electrode there are provided grooves guiding the flow of gas bubbles admitted from the above- 2 said openings over the whole surface of the immersed portion of the electrode, thereby preventing it from electrochemical destruction.

The end wall of the immersed portion of the electrode is preferably convex in shape. This provides for smooth washing of the entire portion of the electrode immersed in the melt with the gas flows, which create protective envelope.

The present device made according to the invention successfully solves the previously described technical problem.

The invention will be further described in detail with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a device for electroslag casting of ingots;

FIG. 2 is a bottom view of the non-consumable metal electrode;

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a general view of a device for electroslag melting of hollow ingots; and

FIG. 5 is a view taken along the line VV in FIG. 4, the view looking in the direction of the arrows.

As shown in FIG. 1, the device for electroslag casting of ingots includes a cooled mold 1, a cooled pan or bottom plate 2, a non-consumable cooled metal electrode 3 and consumable electrodes 4. The non-consumable electrode 3 has a sidewall 3a, end wall 3b and a bore 3c. The end wall 3a and the side wall adjacent thereto is provided with opened end grooves 7 with the grooves 7 being provided with openings 6 which communicate with the bore 30 of the electrode. The portion of the electrode 3 provided with the openings 6 and grooves 7 is immersed into a slag bath 5 (FIGS. l-3). The device is fed from a power supply source 8 inserted between the non-consumable electrode 3 and the pan 2.

The device operates as follows:

Prior to starting the electroslag process, the non-consumable electrode 3 is placed in the mold 1, with cooling liquid 9 and gas 10 (or a gas mixture) being fed into the bore 30 of the electrode. Molten slag is poured into the mold 1 to form a slag bath 5. The gas 10 is fed through the openings 6 in the non-consumable electrode 3 as a flow of gas bubbles l 1 directed to the zone of the slag bath 5 surrounding the non-consumable electrode 3, so that a gas envelope is formed to protect the non-consumable electrode 3 from electrochemical destruction. The gas bubbles, by means of the grooves 7, are uniformly distributed over the whole surface of the portion of the electrode 3 immersed in the slag bath 5. Next a voltage from an a-c or dc supply source is applied to the non-consumable electrode 3 and pan 2, with the consumable electrodes 4 being lowered into the slag bath. The consumable electrodes 4 start to melt down as soon as their lower ends come in contact with the slag bath 5. The molten metal obtained due to 3 non-consumable electrode 3 with the gas bubbles 11.

In FIGS. 4 and 5 is illustrated an embodiment for electroslag casting of hollow ingots which includes a cooled mold l3 and a pan 14 provided with an opening, a consumable electrode 15 and a cooled pan 16 for shaping the inner space of an ingot 17 used as a nonconsumable electrode.

The walls of the pan 16 at the level of metal bath 18 and slag bath 19 are provided with channels 20 with openings 21 for feeding the gas from a gas distributor 22.

The channels 20 provided with the openings 21 in the walls of the pan 16 are located tangentially to the axis thereof as can be seen in FIG. 5.

FIG. 4 also shows a power source 23 inserted between the consumable electrode 15 and pan 16. Such a device operates similarly to the above-described device, with the difference being that during the entire process of casting the hollow ingot 17, a mutual displacement of the mold 13 and the pan 14 securing the ingot 17 occurs at a speed close to the speed of lifting of the slag bath 19.

In the above-described embodiments, the immersed portion of the non-consumable electrode is washed with gas flows under a pressure which is not lower than the hydrostatic pressure created by the column of the melt whose height is equal to the length of the portion of the non-consumable electrode immersed in the melt.

4 The gas flow may be composed of inert gases such as helium and argon, as well as other gases, reagents, gas and gas-and-powder mixtures.

However, in case convective streams are present in the melt, the preliminarily immersed portion of the non-consumable electrode is to be washed with the gas streams under a pressure which can be lower than the hydrostatic pressure created by said melt column.

We claim:

l. A device for electroslag casting of ingots which comprises a mold, a bottom plate therefor, consumable electrodes, a non-consumable cooled metal electrode to be partially immersed in a melt, and an electric current source provided between the non-consumable electrode and the bottom plate, said non-consumable electrode having a a sidewall, an end wall and a bore through which a gas flow passes, the end wall and the sidewall adjacent thereto having grooves, the grooves being provided with openings in communication with the bore, with the grooves serving for guiding a flowof gas bubbles admitted from the openings over the whole surface of the partially immersed non-consumable cooled metal electrode, thus preventing it from electrochemical destruction.

2. The device as claimed in claim 1 in which the end wall of the electrode is convex. 

1. A device for electroslag casting of ingots which comprises a mold, a bottom plate therefor, consumable electrodes, a nonconsumable cooled metal electrode to be partially immersed in a melt, and an electric current source provided between the nonconsumable electrode and the bottom plate, said non-consumable electrode having a a sidewall, an end wall and a bore through which a gas flow passes, the end wall and the sidewall adjacent thereto having grooves, the grooves being provided with openings in communication with the bore, with the grooves serving for guiding a flow of gas bubbles admitted from the openings over the whole surface of the partially immersed non-consumable cooled metal electrode, thus preventing it from electrochemical destruction.
 2. The device as claimed in claim 1 in which the end wall of the electrode is convex. 